Looking for good youtube channels doing long form videos on older history (pre-1700), one I binged through recently was Ancient Americas (https://www.youtube.com/c/AncientAmericas). They don't need to be leftist, just well-sourced and not obviously chuddy.
Uploads slowly and very long documentary-esq vids but I love The Histocrat
The greatest thing is for both his vids and his podcast (also uploaded to the channel) is he and his cohost cite themselves relentlessly